The most common and most likely answer to this crossword clue is the 4 letter word TUBE
I've seen this crossword clue in The Guardian
T
U
B
E
More clues leading to the result TUBE
- TV channel
- Sort of train from east, however, going west
- Transport system, however revolutionary, ultimately late
- Bath line’s terminus in subterranean railway
- Pipe travelling underground, bewilderingly expensive for starters
- One form of pasta if potato, say, is short
- Train from Bath East
- Rotavate earth, except underground
- Box extremely stupid person
- Cylinder cut potato, perhaps
Buddy explains!

The straight part
We know that "One form of pasta" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one form of pasta = tube.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does TUBE mean?
TUBE noun- Anything that is hollow and cylindrical in shape.
- An approximately cylindrical container, usually with a crimped end and a screw top, used to contain and dispense semiliquid substances.
- (often capitalized as Tube) The London Underground railway system, originally referred to the lower level lines that ran in tubular tunnels as opposed to the higher ones which ran in rectangular section tunnels. (Often the tube.)
- A tin can containing beer.
- A wave which pitches forward when breaking, creating a hollow space inside.
- A television.
- An idiot.
- To supply with, or enclose in, a tube.
- To ride an inner tube.
- To intubate.